Please include a main to see the output.

Question $3$:

Write a method in the Demo class $($name it reverseString$),$ call the method from the main$()$ and pass a string to it$.$ This method will do the following:

Receives a string $($sentence$,$ not just one word$).$

Stores the received string in an linkedlist$-$based stack

Prints the sentence in reverse.

Example:

Call statement: reverseString$("$Testing my reverseString method"$)$;

output: dohtem gnirtSesrever ym gnitseT

Question $4$:

Write a method in the Demo class $($name it reverseNumber$),$ call the method from the main$()$ and pass an integer to it$.$ This method will do the following:

Receives an integer.

Stores the received integer in an array$-$based stack

Prints the integer in reverse.

Example:

Call statement: reverseNumber$(5467)$;

output: $7645$

$**$Demo class below$**$

public class LinkedStack $\{$

private Node top $=$ null;

public boolean empty$()\{$

return top $==$ null;

$\}$

public void push$($String s$)\{$

top $=$ new Node$($s$,$ top$)$;

$\}$

public String pop$()\{$

String retValue;

if $($empty$())\{$

throw new IllegalStateException$()$;

$\}$ else $\{$

retValue $=$ top.element;

top $=$ top.next;

return retValue;

$\}$

$\}$

public String peek$()\{$

if $($empty$())\{$

throw new IllegalStateException$()$;

$\}$ else $\{$

return top.element;

$\}$

$\}$

public String toString$()\{$

Node ref $=$ top;

String toPrint $=""$;

while $($ref $!=$ null$)\{$

toPrint $+=$ ref.element;

ref $=$ ref.next;

$\}$

return toPrint;

$\}$

$//$ Node class used for linked list

private class Node $\{$

String element;

Node next;

Node$($String e$,$ Node n$)\{$

element $=$ e;

next $=$ n;

$\}$

$\}$